Q: How to install some ebuild which are masked.
A: Dont use ACCEPT_KEYWORDS="x86" because it tends to break!
There are several methods to do this.
1) Just add "<package name> amd64" to your /etc/portage/package.keywords
2) You can use "ekeyword" from the gentoolkit-dev package:

Code:

ekeyword \amd64 /usr/portage/x11-libs/wxGTK/wxGTK-2.5.1-r1.ebuild

3) edit the ebuild manually like and add "amd64" in KEYWORDS variable, for example

Code:

nano /usr/portage/x11-libs/wxGTK/wxGTK-2.5.1-r1.ebuild

and then just "emerge wxGTK".

For me number 1) only works if instead of amd64 I use a keyword that is in the ebuild. For example, if there is only an x86 keyword in the ebuild, I then have to put '<package_name> x86'.

Also <package_name> is the full name including the category and unless you want to edit the package.keywords file alot you should pick a version and put '>=' at the beginning of the line. Similar to how dependecies are listed in the ebuild.

Q: Will performance suffer if I use 32-bit emulation?
A: The 32-bit binaries will run as fast as you'd expect from a modern processor. The performance loss is insignificant.

Q: Example CFLAGS for amd64
A: gcc-3.4 : CFLAGS="-march=athlon64 -O2 -pipe"
gcc-3.3 : CFLAGS="-O2 -pipe"
Some agressive flags I have that worked ok for me "-frename-registers -fweb and -fomit-frame-pointer". GCC 3.4 produced code is quicker, but it is not compatible with everything now.

Q: How to compile in 32 bits on amd64?
A: You have to compile gcc with "multilib" in your USE flags. Then take the software you want to compile and run

Code:

CFLAGS="-march=i386 -m32 -Xlinker=-m32" ./configure

It works for me in 99% of cases, but wine won't compile this way, not everything Check the question below about wine. Remember, You will also need 32 bit libs for your package installed. I tested this method so far on the freespace2 linux port, libaal, openal and it worked.

Q: How do I enable nx (non-execute) on amd64
A: This kernel boot parameters do the job : noexec=on and noexec32=on for 32 bit applications. Here are some amd64 boot parameters.

Q: How do I enable Cool and Quiet/Cool'n'Quiet/powernow
A: kernel config:
Power management options --->
[*] Power Management support
CPU Frequency scaling --->
[*] CPU Frequency scaling
<*> CPU frequency table helpers
<*> AMD Opteron/Athlon64 PowerNow!
You should also enable different governors here. I use "userspace" to change speed with

You can also use /proc/sys/cpu/0/speed interface for that untill it gets deprecated. You can also use a special daemon (like cpudyn or powernowd or cpufreq) to manage speed automatically.
please correct me/add here because I dont use dynamical services and dont have a clue about them

The conf file is pretty self-explaining.
To install start "grub" and type "install (hd0)" to install it on mbr of the first (the one you boot from) drive or install (hd0,0) to install it for example on the first partition of this drive. You can also use "install (hd1)" to install it on the mbr of the second drive. It doesn't matter wether first boot drive is scsi/ide/sata, as long as you boot from it, it is hd0 for grub. The second thing you type here is to specify the partition where grub is installed. Example: "root (hd0,1)" for boot drive, second partition. Then grub should recognise the filesystem and you can boot using your /boot/grub/grub.conf.

Q: My 32 bit software needs * libraries.
A: 1) Check if you installed all emul- ebuilds with "emerge -s emul-linux-x86"
2) Use filename on google to get library name, get the 32 bit library from some other 32 bit distribution (I prefer fedora core 2). Convert the rpm to tar.gz by using rpm2targz. Copy unpacked libs in /usr/lib32, run ldconfig. Hope it works

Q: How to install some ebuild which are masked.
A: Dont use ACCEPT_KEYWORDS="x86" because it tends to break!
There are several methods to do this.
1) Just add "<package name> amd64" to your /etc/portage/package.keywords
2) You can use "ekeyword" from the gentoolkit-dev package:

Code:

ekeyword \amd64 /usr/portage/x11-libs/wxGTK/wxGTK-2.5.1-r1.ebuild

3) edit the ebuild manually like and add "amd64" in KEYWORDS variable, for example

Code:

nano /usr/portage/x11-libs/wxGTK/wxGTK-2.5.1-r1.ebuild

and then just "emerge wxGTK".

Q: Quake3-based games or (some other 32 bit 3d software) do not work and exit with this

A: Try exporting LD_LIBRARY_PATH="/usr/lib32/opengl/nvidia/lib/" and then running the game.
Works sometimes with other software which uses 3d, like cedega, somone reported it worked for qtopia.
It seems latest opengl-update also should fix the problem.

Q: AGP on amd64 ?
A: With nvidia you have to use in-kernel AGP, it is automatically enabled if you enable "IOMMU", else you could enable AGP in Device Drivers -> Character Devices -> /dev/agpgart. Then you have to set in your xorg.conf in section "Device"

Code:

Option NvAGP="2"

Check with "cat /proc/driver/nvidia/agp/status"
Ati: no idea - dont have that ;P Suggestions will be greatly appresiated.

Q: My flash / java / some other 32bit plugin doesn`t work.
A: At the moment if you want to use 32 plugins with 64 bit browser your only choice is to use konqueror or to use 32 bit browser. How to use 32 bit plugins with 64 bit Konqueror: https://forums.gentoo.org/viewtopic.php?t=216959

Q: What about Memory?
A: Note, that athlon64 is quite picky about it's memory because of the onboard memory controller. The only way to fix problems with memory is a bios update or to lower the timings in bios. Check this thread.

Because i was not that active in the forums lately. I also think it should be rewritten because many things have changed. Make some suggestions what to change and i will update it .
p.s. i changed the "yous" and added some stuff.
@slougi can u post exatly what to change. Also sorry, english is not my native language. I also would give you writing rights to the post but since i'm not a moderator i can't actually do so.

About Cool&Quiet -> someone start it at 2.6.12-rcX ??? today i tried but i cant :/ on 2.6.11.X there is no problem, everything is working fine. I want to use rc kernels because my sensors works corectly only with rcX .

I cant help you with lm_sensors caus i use just plain /sys/bus/i2c/devices/0-0290/temp2_input device node. If its too hot the computer shuts down. I also have it87 with gigabyte k8t800 board and it works, all but fans which work only with windows program. I also havent tried 2.6.12rc series. Does your it87 moule loads? check dmesg , if it does, you might try my solution
Well people who know python/bash scripting are gonna laugh but i did this: